1. Field of the Invention
The disclosures herein generally relate to a temperature control device, an image display apparatus and a vehicle.
2. Description of the Related Art
Recently, market expectations for applications, by which drivers can recognize warnings and information with small sight line movement, have increased, and technology developments for head-up displays (HuD) installed on vehicles have been advanced. Especially, with the progress of on-vehicle sensing technologies, represented by the term ADAS (Advanced Driving Assistance System), vehicles have become able to capture information on travelling environments and occupants in vehicles. Then, the HuD has received attention as an “exit of ADAS” for transmitting the information to drivers.
As a projection system of the HuD, a “panel system” for expressing an intermediate image with an imaging device, such as a liquid crystal device or a digital mirror device (DMD), has been known. Moreover, there is a “laser scanning system” for scanning with laser beams emitted from laser diodes (in the following, referred to as “LD”) with a two-dimensional scanning device to form an intermediate image.
Especially, in the laser scanning system, in the latter case, different from the panel system in which an image is formed by partially shielding light from an entire screen emission, because it is possible to assign emission/not emission for each pixel, an image with high contrast can be formed. However, the laser diode has temperature dependency, and in a case of use in a high-temperature environment or in low-temperature environment, it is necessary to carry out temperature control such as cooling or heating in order to maintain the temperature of the laser diode within an appropriate range. Then, a technology for assigning Peltier devices to respective laser diodes for RGB with different wavelengths, to control temperatures of the respective laser diodes has been proposed (for example, see Japanese Unexamined Patent Application Publication No. 2014-195218).